In GIS, Topology is a set of rules which define the relationship between points, lines and polygons.


According to the text book, topology is the “property that describes adjacency and connectivity of features. A topological data structure encodes topology with the geocoded features”. Another definition is “The numerical description of the relationships between geographic features, as encoded by adjacency, linkage, inclusion, or proximity. Thus a point can be inside a region, a line can connect to others, and a region can have neighbors. The numbers describing topology can be stored as attributes in the GIS and used for validation and other stages of description and analysis”.